phates; and I shall admit with M. Berthier, that

The phosphate of lead is composed of

100.00 lead. 7.29 oxygen. 31.14 acid.

According to this, we find by calculation the following

Since (the proportions of a metallic salt and the oxi dation of the metals being given) we may determine those of all the salts of one and the same kind, we may also (the proportions of acid and oxide of all the metallic salts and the oxidation of a single metal being given) calculate that of all the rest. Thus, upon the supposition that the analysis of the sulphate of lead which I used is exact, and that of the sulphate of barytes (66-5 of barytes and 33:5 of acid) given by M. Berthier is correct also, we find that the new combustible substance extracted from barytes would take for 100 parts 10.77 of oxygen. In the same way, admitting the analysis of the muriate of soda which was communicated to me by M. d'Arcet, viz. 50-73 of alkali and 49.27 of acid, we should find that the new combustible substance extracted from soda takes 40.21 of oxygen: about four times more than the foregoing.

We know that lead, silver, and mercury at the minimum of oxidation form insoluble salts, with a very great number of acids. These metals are precisely those which form neutral salts, or nearly so, take less oxygen, and consequently less acid. We can easily conceive, therefore, how all the salts in which the oxide is at the minimum of oxidation, have more tendency to insolubility than those in which the oxide is at the maximum. It is a consequence of this general law, that when there is plenty of any insoluble principle in a compound, the latter has more tendency to insolubility than when it is a souble principle which prevails in it. The mercury at the minimum forms an insoluble salt; but when it is at the maximum, it

gives a salt which enjoys a great solubility, as well as all the metallic salts which take much oxygen.

I shall not extend this memoir further, as I think I have related a sufficient number of facts to establish the principle which is the object of it, and to make all its consequences apparent. The proportions of acid in the salts depending on the quantity of oxygen which the bases contain, it would be desirable if chemists would direct their attention, on the oxidation of the metals and on the proportions most easy to determine, to one or two salts in each genus. We should thus obtain the proportions of a great number of salts, and we should even have the advantage of calculating the limits of those of the acid salts, in proportion as they should approach neutrality more and more. For it must be well remarked, that the excess of acid in a salt is foreign to the saturation, and that it is only necessary to hinder the precipitation of the oxide by destroying its force of cohesion. If, in fact, the oxides were very soluble, they would all form perfectly neutral salts.

Observation.

When we precipitate a metallic solution by sulphuretted hydrogen alone, or combined with an alkaline base, we obtain a metallic sulphuret or hydro-sulphuret. In the first case, the hydrogen of the sulphuretted hydrogen is combined with all the oxygen of the oxide, and the sulphur forms a sulphuret with the metal. In the second case, the sulphuretted hydrogen is combined directly with the oxide without being decomposed, and its proportion is such that there is enough of hydrogen for saturating all the oxygen of the oxide. The quantity of the hydrogen destroyed, or capable of being so, depends therefore on the oxidation of the metal, in the same way as the quantity of sulphur which may be combined with it. Consequently the same metal, forms as many distinct sulphurets as it is susceptible of degrees of oxidation in its acid solutions. And as these degrees of oxidation are fixed, we ought also to obtain sulphurets with constant proportions, which we may determine very easily, according to the quantity of oxygen of each metal and the proportions of the sulphuretted hydrogen. 1 do not pretend that these sulphurets are the only ones which we can obtain; but I think that we ought to regard them as the true types of the other sulphurets, so much the more as the proportion of the sulphur has an immiediate relation with the quantity of oxygen which the metal had, and as the latter determines of itself the proportion of acid which is combined with it. XXXVI. A con

XXXVI. A concise Description of Schooley's Mountain, in New-Jersey, with some Experiments on the Water of its Chalybeate Spring. By SAMUEL L. MITCHILL, Professor of Natural History in the University of New-York, Representative in the Congress of the United States, &c. &c. Communicated by the Author.

THERE had been so much conversation about Schooley's mountain, that in the beginning of July 1810 I executed the desire I had long entertained of visiting it.

Schooley's mountain is part of a chain which extends in a north-easterly and south-westerly direction across the state of New-Jersey. It may be traced from the Highlands of New-York. Towards the Hudson, its ridges divide the plains of Rockland county from those of Orange, being denominated the Haverstraw, Warwick, Skunemunk, and Stirling mountains, and being distinguished locally by several other names. Towards the Delaware, it separates the upper waters of the Raritan from those of the Musconetcunck, and passing from Sussex through Morris and Hunterdon counties, is called, somewhat to the southward of Philipsburg, the Musconetcunck mountain. The more noted portion of its middle region is termed Schuyl's Hills, or Schooley's Mountain. The latter name is the most prevalent, and is derived from a family which was formerly a considerable proprietor of the soil thereabout. The former appellation is probably a mere abbreviation or corruption of it.

This ridge discharges the water from its north-west side, partly through the Wallkill, into the Hudson, a little to the eastward of Esopus, after traversing Sussex county, in NewJersey, and Orange and Ulster, in New-York. Part also empties into the Hudson through Murderer's Creek, at New-Windsor. Another portion is collected into the Musconetcunck river; and running almost parallel with the mountain, falls into the Delaware, not many miles south of Eastown. The water from the south-east side feeds the upper streams of the Pasaick, which, after visiting Orange, Rockland, Morris, Essex, and Bergen counties, falls into Staten Island sound, to the southward of Newark. The stream called the Black river beyond Mendham, and that termed South-branch, watering Dutch valley, neither of them reach the Delaware, but empty into the Raritan, some distance above Brunswick.

Thus these heights completely divide the waters of NewJersey

Jersey. Not a single stream is known to pierce them. From their north-western slope, all their streams find their way into the Hudson and the Delaware. From their south

eastern declivity, their currents travel to the ocean by Newark and Raritan bays. They have, however, no pretensions to be classed with the Shawangunk mountains, which are a distinct chain, and make part of the great Alleghany, that traverses the continent to the confines of Georgia. Nor have they any connexion with the Kaatskill mountains, which are themselves quite detached from the Shawangunk. Schooley's mountain is of more moderate elevation than either. Geometrical measurement has ascertained that the height of Schooley's mountain above its immediate base is more than six hundred feet. And a calculation made by approximation, on the falls of water at the different niill-dams along the hurrying channel of the Musconetcunck, to its junction with the Delaware, and on the descent thence to Trenton, makes the position of that base to be nearly five hundred feet more above tide-water. The elevation above the level of the ocean does not, therefore, in all probability, much exceed eleven hundred feet. And this is about the height ascribed to Anthony's Nose, in the Highlands of New-York, by Mr. Knight.

The elevation is, nevertheless, considerable enough to influence its temperature. The heats of summer are not so great as in the valleys. Droughts are less common and piuching. Snow falls earlier, and lies longer than in the adjacent plains. The warmth of a copious spring of pure water, as it issued out of the sand near the top of the moun tain, was only 50 degrees, while the temperature of the water gushing from the briskest springs on the north side of Long island, and drawn from the deepest wells at NewYork, is 54 degrees. The spring water on the summit of Schooley's mountain is, therefore, four degrees colder than that around New-York.

This mountain is not a mass of stratified rocks, piled upon each other from bottom to top. There is no peculiar difficulty in travelling over it. The predominating materials are clay and sand, forming a good loam; which, though generally not argillaceous enough for the formation of bricks, is, at the same time, gravelly enough for the growth of grass and grain. Yet rocks are thickly distributed over its face and along its sides. They are mostly detached, though some of them are of large dimensions. They consist chiefly of feldspar and quartz: the quartz is prone to be semipellucid, and is granular or angular, resembling Vol. 37. No, 155. March 18!1.

Ο

coarse

coarse marine salt. The feldspar is mostly whitish, sometimes reddish, and presents less of the polished fracture than the American feldspars usually do. It has the appearance of a more imperfect formation, or of having undergone a partial decomposition. These two ingredients make up the bulk of the rocks. Many masses may be examined without observing a vestige of mica. Abundant as mica is almost every where in these parts, with the mixtures of feldspar and quartz, in our primitive rocks, it is remarkably deficient here. Now and then a little schistus, or horneblende, is found embodied and compacted with the quartz and feldspar. Grains of yellow pyrites also sometimes occur. Rust, ochre, and other indications of iron, are dispersed extensively both through the rocks and the soil. Iron ore is indeed so plentiful, that furnaces are in operation both in the eastern and western districts of the chain. Much of it is magnetical, and its action is so powerful upon the needle, that surveyors of land often find it very difficult to employ the compass. It would be possible to collect great quantities of the magnet, and of other ores of iron in the middle region. Towards the foot of the hills, limestone is found skirting the valleys along, and is calcined in quantity sufficient for all œconomical uses.

Among the natural productions thereabout, are masses of excellent flint stones. They lie along the valleys and side hills, where they have been washed bare; and are sufficient in quantity and quality for domestic supply of our musketry. They are more pure and of a better fracture than those contained in the lime-stone near Niagara. And when this important article of public defence shall be thought worthy of being improved by the citizens, there seems to be in New-Jersey an inexhaustible supply for our fire-arms.

A turnpike road has been completed from the city of Jersey, at Powleshook, to the summit of Schooley's mountain. The travelling is excellent the whole distance. This is just fifty miles from New-York city. Estimating the width of the Hudson to be two miles, the distance to Newark is nine, to Springfield seven, to Chatham five, to Morristown seven, to Mendham six, to Blackriver six, to Dutch-valley five, and to the Mineral Spring on the eastern or further side of the mountain, three miles. Through such a succession of thriving villages, and amidst a country pleasingly checkered with forests and farms, the rise of the first five hundred feet is surmounted in about forty-seven miles, as the traveller passes over a surface of easy eleva